eKhSACIR інституційному репозитарії Харківської державної академії культури
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Effect of resolution, reconstruction settings, and segmentation methods on the numerical calculation of saturated soil hydraulic conductivity from 3D computed tomography images
No full textInternational audienceOver the last decade, computed tomography (CT) images have been used increasingly to gain a more complete understanding of the microscale parameters that control the soil processes. Images that are used for that purpose typically are subjected to a number of successive treatments. This article evaluates for a sandy-loam soil, the impact of two CT scan resolutions (26 and 54 m), three noise reduction levels, four settings of conversion from a 32-bit to an 8-bit image and four segmentation methods (Hapca et al., 2013; Houston et al., 2013a; Schlüter et al., 2010; Otsu, 1979) in an incomplete factorial design, on the morphological metrics and on the numerical calculation of the saturated hydraulic conductivity, . The calculations reveal variations of up to two orders of magnitude of . Houston’s and Schlüter’s segmentations appear the most sensitive to the identification of gray voxels in the key throats controlling the water flow. When combined with high noise reduction levels they produce in some extreme cases disconnections of the percolating pores. Hapca’s segmentation produces more robust results. The Kozeny-Carman relation successfully predicted the saturated hydraulic conductivity when using the critical path diameter as the characteristic length, instead of the macroscopic hydraulic radius which appears too integrative to identify the extent of the variation of key throats
Field measurement and modelling of chlorotoluron and flufenacet persistence in unamended and amended soils
No full textInternational audienceThe dissipation and persistence of two cereals herbicides, chlorotoluron and flufenacet, were studied in a field experiment including three replicated plots of unamended soil (S), soil amended with spent mushroom substrate (S + SMS), and soil amended with green compost (S + GC), during the winter wheat cultivation campaign. The SMS and GC organic residues were applied to the soil at rates of 140 or 85 t residue ha−1, and herbicides were sprayed as Erturon® and Herold® formulations for chlorotoluron and flufenacet, respectively. Concentrations of both herbicides and of their metabolites were regularly measured in the three soil treatments (0–10 cm) from 0 to 339 days. The dissipation kinetics fitted well the single first order (SFO) model, except that of chlorotoluron that fitted the first order multi-compartment (FOMC) model better in the unamended soil. The dissipation rates of herbicides were lower in amended than in unamended soils. The results also showed that the DT50 of chlorotoluron (66.2–88.0 days) and flufenacet (117–145 days) under field conditions were higher than those previously obtained at laboratory scale highlighting the importance of the changing environmental conditions on the dissipation process. Similarly, the formation of chlorotoluron and flufenacet metabolites under field conditions was different from that previously observed in the laboratory. The performance of the MACRO pesticide fate model, parameterized with laboratory data, was then tested against field data. There was a very good agreement between measured and simulated chlorotoluron residue levels in the three soil treatments, while the ability of the model to reproduce the dissipation of flufenacet was good in the unamended soil and very good in S + SMS and S + GC soils. MACRO might be used to estimate the remaining amounts of herbicides in amended soils from degradation data previously obtained at laboratory scale. This would help to manage herbicide doses in different environmental conditions to preserve the sustainability of agricultural systems
Sentinel-1 and Sentinel-2 data for characterising the states of continental surface over a semi-arid region en Tunisia
No full textInternational audienceRadar and optical data have shown great potential for monitoring soil and canopy parameters. In this context, Sentinel-1 (S-1) and Sentinel-2 (S-2) time series were used to retrieve different parameters using models and different algorithms. The main objective of this study is to analyze the potential a synergetic use of radar and optical data for the estimation of soil moisture, irrigation detection and soil texture over agricultural areas for sustainable management of water and soil resources. First, the radar signal is simulated using a semi-empirical backscattering model over bare soil and vegetation cover. The Water Cloud Model parameterized with NDVI for vegetation contribution allows a good estimation of soil moisture by inversion techniques. Soil moisture time series were then developed for the spatialization of irrigation and soil texture. In this study, both products have shown good agreement with in situ measurements
No-regret Pollution Abatement Options: A Correction of Bréchet and Jouvet (2009)
No full textInternational audienceIn "Why environmental management may yield no-regret pollution abatement options", Ecological Economics, 2009, Bréchet and Jouvet claim to have theoretically shown that profits maximizing firms can reduce pollution compared to laissez-faire and increase their profits. We correct multiple errors in their paper, with the conclusion that their claim no longer stands
Anther-smut fungi from more contaminated sites in Chernobyl show lower infection ability and lower viability following experimental irradiation
No full textInternational audienceThe long-term contamination that followed the nuclear disaster at Chernobyl provides a case study for the effects of chronic ionizing radiation on living organisms and on their ability to tolerate or evolve resistance to such radiation. Previously, we studied the fertility and viability of early developmental stages of a castrating plant pathogen, the anther-smut fungus Microbotryum lychnidis-dioicae, isolated from field sites varying over 700-fold in degree of radioactive contamination. Neither the budding rate of haploid spores following meiosis nor the karyotype structure varied with increasing radiation levels at sampling sites. Here, we assessed the ability of the same M. lychnidis-dioicae strains to perform their whole life cycle, up to the production of symptoms in the plants, that is, the development of anthers full of fungal spores; we also assessed their viability under experimental radiation. Fungal strains from more contaminated sites had no lower spore numbers in anthers or viability, but infected host plants less well, indicating lower overall fitness due to radioactivity exposure. These findings improve our understanding of the previous field data, in which the anther-smut disease prevalence on Silene latifolia plants caused by M. lychnidis-dioicae was lower at more contaminated sites. Although the fungus showed relatively high resistance to experimental radiation, we found no evidence that increased resistance to radiation has evolved in populations from contaminated sites. Fungal strains from more contaminated sites even tolerated or repaired damage from a brief acute exposure to γ radiation less well than those from non-or less contaminated sites. Our results more generally concur with previous studies in showing that the fitness of living organisms is affected by radiation after nuclear disasters, but that they do not rapidly evolve higher tolerance
A Mapping Review on Urban Landscape Factors of Dengue Retrieved from Earth Observation Data, GIS Techniques, and Survey Questionnaires
No full textInternational audienceTo date, there is no effective treatment to cure dengue fever, a mosquito-borne disease which has a major impact on human populations in tropical and subtropical regions. Although the characteristics of dengue infection are well known, factors associated with landscape are highly scale dependent in time and space, and therefore difficult to monitor. We propose here a mapping review based on 78 articles that study the relationships between landscape factors and urban dengue cases considering household, neighborhood and administrative levels. Landscape factors were retrieved from survey questionnaires, Geographic Information Systems (GIS), and remote sensing (RS) techniques. We structured these into groups composed of land cover, land use, and housing type and characteristics, as well as subgroups referring to construction material, urban typology, and infrastructure level. We mapped the co-occurrence networks associated with these Remote Sens. 2020, 12, 932 2 of 82 factors, and analyzed their relevance according to a three-valued interpretation (positive, negative, non significant). From a methodological perspective, coupling RS and GIS techniques with field surveys including entomological observations should be systematically considered, as none digital land use or land cover variables appears to be an univocal determinant of dengue occurrences. Remote sensing urban mapping is however of interest to provide a geographical frame to distribute human population and movement in relation to their activities in the city, and as spatialized input variables for epidemiological and entomological models
Microgeographic adaptation and the effect of pollen flow on the adaptive potential of a temperate tree species
No full textNational audienceRecent interest for microgeographic adaptation, i.e. adaptation at spatial scales compatible with substantial amount of gene dispersal, offers to reconsider the scale at which evolution occurs (Richardson et al. 2014). Whether gene flow is constraining or facilitating local adaptation at this fine spatial scale remains an unresolved question. Too important gene flow would overwhelm the effects of natural selection and decrease local adaptation along environmental gradients. Conversely, gene flow, and particularly long-distance dispersal events, could play a major role in resupplying the genetic variation of populations and favouring the spread of beneficial alleles (Kremer et al. 2012). Hence, the high dispersal capacities of trees are often assumed to be the main process maintaining the large levels of genetic variation measured in their natural populations. However, evidences for microgeographic adaptation and the quantitative assessment of the impact of gene flow on adaptive genetic variation are still limited in most temperate trees. Here, we sampled 60 open-pollinated families of European beech (Fagus sylvatica L.) from three natural plots, spreading along a short elevation gradient (∼1.5 km) at the warm margin of this species distribution. We analysed the phenotypic and genotypic data of ∼2,300 seedlings grown in a common garden. We focused on 11 potentially adaptive traits with significant heritabilities (Gauzere et al. 2016) and tested for signature of local selection on quantitative trait differentiation. We then identified the offspring likely originating from local or distant pollen immigration events and quantified the role of gene flow in increasing locally the additive variance of traits under selection. We found a significant signal of adaptive differentiation among plots separated by less than one kilometre, with local selection acting on growth and phenological traits. We found that trees in the plots at high elevation, experiencing the lowest temperature conditions, flushed earlier and had a higher height and diameter growth in our common garden than trees from the plot at low elevation. Beech populations originating from higher longitude or elevation have also been shown to be genetically earlier in provenance tests, suggesting that these populations evolved phenological traits promoting a longer vegetation period. At this southern margin of the species, the reduced allocation to stem growth at the low elevation plot is likely an adaptive response to drought, which has previously been described by comparing marginal vs central beech populations. Consistently with theoretical expectations, our results suggest a beneficial effect of pollen dispersal by increasing the genetic diversity for these locally differentiated traits. These effects were quantitatively high, with more than twice higher genetic variance for immigrant than local offspring, although with large standard errors around estimates. Our results highlight that local selection is an important evolutionary force in natural tree populations, and provide a strong evidence that adaptive genetic differentiation can occur despite high gene flow. For the two genetically differentiated traits, our analyses suggested a beneficial effect of pollen dispersal by increasing genetic diversity after one episode of reproduction. The findings suggest that conservation and management interventions to facilitate movement of gametes along short ecological gradients would boost genetic diversity of individual tree populations, and thereby enhance their adaptive potential
Milk proteins: Digestion and absorption in the gastrointestinal tract
No full textInternational audienceIn the industrialized world, dairy products constitute an important part of the diet, especially in northern Europe and North America. In these regions, milk products contribute around 30% of the total dietary protein supply and represent about 65% of the intake of animal protein. The protein content of cow’s milk ranges from 32 to 35 g/L. There are two major types of milk protein: the caseins (80%), which are represented by four distinct proteins (αs1-,αs2-, β-, and κ-caseins), and the whey proteins (20%), which are represented by proteins such as β-lactoglobulin, α-lactalbumin, and lactoferrin. These two families of proteins are opposite in terms of structure. Caseins exhibit a loose and highly flexible structure and are associated into a supramolecular structure called the micelle, whereas whey proteins have a globular, well-defined three-dimensional structure. These structural differences between the two families markedly affect the behavior of these proteins in the gastrointestinal tract and particularly their susceptibility to hydrolysis by the digestive enzymes. The nutritive value of proteins, including milk proteins, is generally associated with their capacity to provide two components: nitrogen (related to protein quantity) and essential amino acids (related to protein quality). The overall nutritional efficiency of protein is most commonly measured via nitrogen retention, which assesses protein retention. In terms of protein quality, the nutritive value is related to the amino acid composition and the bioavailability of these amino acids. The content and the bioavailability of indispensable amino acids, that is, those that cannot be synthesized in the body and consequently must be supplied through the diet, are of particular concern
